I will choose coin that is undervalued and scalp it daily so i will accumulate a lot of coins. or yet invest it in a low supply but a big potential in the future project. in my perspective i will choose top 10 in the cmc.
It seems to me that even considering some examples for an investment of $ 50 is not worth it, because it will take a lot of time to earn some money on this. I think that $ 50 is very small.